Silicon-on-insulator (SOI) substrates are widely used in the microelectronics industry.
One known method of the state of the art for transferring a layer of silicon from a donor substrate to a receiver substrate consists in forming an embrittlement zone in the donor substrate, bonding the donor substrate and the receiver substrate, and then detaching the donor substrate from the receiver substrate by breaking at the embrittlement zone, notably via a suitable heat treatment.
However, breaking induces defects that can be more or less extensive in the receiver substrate and/or the donor substrate.
For example, in the case of a post-breaking substrate implanted with hydrogen ions, roughness of several tens of angstroms (50-80 angstroms RMS) is obtained.
Consequently, to manufacture substrates in which an ultrathin layer of silicon is necessary (roughly 12 nm), for example, fully-depleted silicon-on-insulator (FD-SOI) substrates, it is necessary to transfer a thickness of about 200 nm to 250 nm of silicon, insofar as a large thickness is consumed in surface-smoothing processes.
The invention, thus, proposes to mitigate, at least in part, the disadvantages of the state of the art.